Network traffic shaping by enforcing usage quotas is known. Conventionally, shaping of network traffic is carried out within a stand-alone device through which the traffic flows. Accordingly, the traffic measurement, the calculation of quotas and the enforcement functions are handled by the device. Conventional traffic shaping techniques have a number of shortcomings. For example, their lack of scalability with respect to the number of wide area network WAN and Internet connections, connection speed, or number of users continue to limit their usage and pose challenging tasks.